[1] [1] Sachdev S. Quantum phase transitions[M]. Cambridge University Press,1999, 229-239. DOI: 10.1016/B0-12-512666-2/00132-2.

[2] [2] Bulla R, Vojta M. Quantum phase transitions[J]. Reports on Progress in Physics, 2003, 66(12): 2069. DOI: 10. 1002/chin.200313203.

[4] [4] Zhao X Q, Liu N, Liang J Q. Collective atomic-population-inversion and stimulated radiation for two- component Bose-Einstein condensate in an optical cavity[J]. Optics Express, 2017, 25(7): 8123-8137. DOI: 10.1364/OE.25.008123.

[5] [5] Plascak J A. Mean field renormalisation group for the spin-1/2 anisotropic Heisenberg model[J]. Journal of Physics A General Physics, 1999, 17(11): L597. DOI: 10.1088/0305-4470/17/11/008.

[6] [6] Aharony A. Tricritical points in systems with random fields[J]. Physical Review B Condensed Matter, 2008, 18(7): 3318-3327. DOI:10.1103/PhysRevB.18.3318.

[7] [7] Lipkin H J, Meshkov N, Glick A J. Validity of many-body approximation methods for a solvable model:(I). Exact solutions and perturbation theory[J]. Nuclear Physics, 1965, 62(2): 188-198. DOI: 10.1016/0029-5582(65)90862-X.

[8] [8] Meshkov N, Glick A J, Lipkin H J. Validity of many-body approximation methods for a solvable model:(II). Linearization procedures[J]. Nuclear Physics, 1965, 62(2): 199-210. DOI: 10.1016/0029-5582(65)90863-1.

[9] [9] Glick A J, Lipkin H J, Meshkov N. Validity of many-body approximation methods for a solvable model:(III). Diagram summations[J]. Nuclear Physics, 1965, 62(2): 211-224. DOI: 10.1016/0029-5582(65)90864-3.

[10] [10] Shapiro D S, Pogosov W V, Lozovik Y E. Universal fluctuations and squeezing in a generalized Dicke model near the superradiant phase transition[J]. Physical Review A, 2020, 102(2): 023703. DOI: 10.1103/PhysRevA.102.023703.

[11] [11] Zhao X Q, Liu N, Liang J Q. First-order quantum phase transition for Dicke model induced by atom-atom interaction[J]. Communications in Theoretical Physics, 2017, 67(5): 511-519. DOI: 10.1088/0253-6102/67/5/511.

[12] [12] Zhao X Q, Liu N, Bai X M, et al. Dicke phase transition and collapse of superradiant phase in optomechanical cavity with arbitrary number of atoms[J]. Annals of Physics, 2017, 378: 448-458. DOI: 10.1016/j.aop.2017.02.006.

[13] [13] Liu N, Zhao X Q, Liang J Q. Dicke quantum phase transition for a Bose-Einstein condensate in a two-mode optical cavity[J]. International Journal of Theoretical Physics, 2019, 58(1): 558-574. DOI: 10.1007/ s10773- 018- 3954-5.

[14] [14] Bai X M, Bai X Y, Liu N, et al. Multiple stable states and Dicke phase transition for two atoms in an optical cavity[J]. Annals of Physics, 2019, 407: 66-77. DOI: 10.1016/j.aop.2019.04.019.

[15] [15] Emary C, Brandes T. Chaos and the quantum phase transition in the Dicke model[J]. Physical Review E,2003, 67(6): 066203. DOI: 10.1103/PhysRevE.67.066203.

[16] [16] Baumann K, Guerlin C, Brennecke F, et al. Dicke quantum phase transition with a superfluid gas in an optical cavity[J]. Nature, 2010, 464: 1301-1306. DOI: 10.1038/nature09009.

[17] [17] Peter K, Mor M R, Jonathan K, et al. Introduction to the Dicke model: from equilibrium to nonequilibrium and vice versa[J]. Advanced Quantum Technologies, 2018, 59(2): 1800043. DOI: 10.1002/qute.201800043.

[18] [18] Jaynes E T, Cummings F W. Comparison of quantum and semiclassical radiation theories with application to the beam maser[J]. Proceedings of the IEEE, 2005, 51(1): 89-109. DOI: 10.1109/PROC.1963.1664.

[20] [20] Bai X M, Bai X Y, Liu N, et al. Spin squeezing for two atoms in an optical coherent-state cavity[J]. International Journal of Theoretical Physics, 2020, 59(1): 173-180. DOI: 10.1007/s10773-019-04308-z.